Cape Torokina, Bougainville, Northern Solomon Islands November 1, 1943

Guadalcanal, the largest island in the southern Solo­mon Islands, was the site where the string of Japa­nese con­quests, starting in Janunary 1942, finally ran its course. The bloody fight for Gua­dal­canal (August 7, 1942 to Feb­ru­ary 9, 1943) was a recog­nized turning point in the Pacific War. That said, the long island-hopping road from Gua­dal­canal via Bou­gain­ville in the Solomon Islands to the Bis­marck Archi­pel­ago, to the large island of New Guinea, to the Caro­line and Mari­ana island groups and the Philip­pines, then on to Tokyo Bay was three years in dura­tion and would require fighting a stub­born foe across count­less jungle-clad islands and over huge expanses of mostly empty ocean.

The Bougainville Campaign, codenamed Operation Cherry­blossom, launched on this date, Novem­ber 1, 1943, was a sub­ordi­nate series of closely coor­di­nated land and naval oper­a­tions in the Allied grand stra­tegy known as Oper­a­tion Cart­wheel (1943–1944). The stra­tegy entailed bypas­sing and physi­cally iso­lating forti­fied Japa­nese posi­tions in the Western Pacific and seizing weakly defended but strate­gically impor­tant ones—in the words of U.S. Gen. Doug­las Mac­Arthur, Allied Supreme Com­mander, South­west Pacific Area: “Hit ’em where they ain’t.” Actually, Cart­wheel’s ulti­mate goal was to iso­late (“neu­tralize” or “reduce” in the langu­age of the day) Rabaul, the key Japa­nese air, land, and naval bastion on New Britain Island in the Bis­marck Archi­pel­ago, less than 200 miles north of Bou­gain­ville Island, the largest island in the Solo­mons chain. Rabaul, bristling with enemy war­ships and war­planes, menaced the lanes of sea and air commu­ni­ca­tions between the U.S. and its chief allies in the South­west Pacific, Austra­lia and New Zea­land, and it blocked any Allied drive to expel the enemy from New Guinea’s Papuan Peninsula and the Philippines.

The Bougainville Campaign was divided into two phases, one under formal American command, the other under Australian command. The first phase, which ended in Novem­ber 1944, was kicked off by 14,000 U.S. Marines landing and building a strong defen­sive peri­meter around the beach­head at Cape Toro­kina in Empress Augusta Bay on the west side of Bou­gain­ville Island (see map). By late Novem­ber/­early Decem­ber, three air­strips had been estab­lished inside the peri­meter from which to project air­power toward Rabaul. The last air­strip, one suit­able for bomber runs, became fully oper­a­tional at the end of January 1944. These air­strips played an impor­tant role in iso­lating Rabaul, now under daily bom­bard­ment from Bougain­ville and air­bases further south. Through­out 1944 and 1945, follow-on forces from the U.S. Army and then the Aus­tra­lian II Corps arrived as the Allies conducted operations to clear and secure the rest of the island.

Even before the U.S. role in combat wound down, the pos­ses­sion of Bou­gain­ville by either side in the con­flict was of no con­se­quence to the out­come of the Pacific War. The shorter second phase of com­bat oper­a­tions saw just over 30,000 Aus­tra­lian troops going on the offen­sive—ferreting out rem­nants of beaten, starving, dis­ease-ridden, and die-hard Japa­nese soldiers from holes and bunkers that laced the island. Phase 2 was nearly as pro­tracted as the first, lasting until August 21, 1945. It was cer­tainly more deadly. In those last 10 months Japa­nese KIA’s (killed-in-action) num­bered 8,500 out of an esti­mated 18,500–21,500 dead overall. Of the enemy dead, tropical dis­eases and debil­i­tating mal­nu­tri­tion carried off about half of them: 9,800. Sur­viving com­bat were some 21,000–23,500 Japa­nese and Korean laborers. Aus­tra­lian casual­ties exceeded 2,000 dead and wounded; U.S. dead amounted to 727. On the civil­ian side poten­tially 13,000 of the pre-war pop­u­la­tion of 52,000 died, with most islanders’ deaths occurring after 1943.

The Bougainville Campaign and the Allied Plan to Isolate the Strategic Japanese Fortress at Rabaul in the Southwest Pacific

Bougainville Campaign: Map of Bougainville Island, 1943

Above: Map depicting Japa­nese bases and the narrow U.S. Marine inva­sion beaches on the west coast of Bougainville Island at Cape Toro­kina, Novem­ber 1–2, 1943. Admin­is­tered by Aus­tra­lia before March–April 1942, when the Japa­nese seized the island during their advance into the South Pacific, Bou­gain­ville had a pre-war popu­la­tion of 52,000. At 3,591 sq. miles, the fiddle-shaped island (75 miles long and 40–60 miles wide) of thick jungle and large moun­tain peaks in its inte­rior is slightly larger than the U.S. state of Dela­ware. Once secured, the Japa­nese began con­struc­ting a num­ber of air­fields across the island—at Buka Island in the north, at Kahili (near Buin) and Kara in the south, and Kieta on the east coast—along with a naval anchor­age near Buin. These bases helped pro­tect Rabaul, Japan’s major garri­son and naval base on New Britain Island in neigh­boring Papua New Guinea, making Bou­gain­ville an attrac­tive Allied objec­tive. After the war Bou­gain­ville was returned to Aus­tra­lian admin­is­tra­tion as part of the U.N. Trust Terri­tory of New Gui­nea. When Aus­tra­lia granted inde­pen­dence to Papua New Guinea in 1975, Bou­gain­ville became the easternmost province of that new country.

Bougainville Campaign: U.S. Marines approach Cape Torokina Bougainville Campaign: U.S. Marines hit Bougainville Blue Beach 3

Left: Landing craft carrying men and equip­ment of the 3rd Marine Division (a for­ma­tion of the I Marine Amphib­ious Corps) form a circle in Empress Augusta Bay while awaiting landing orders during the inva­sion of Cape Toro­kina, Bou­gain­ville, Novem­ber 1–2, 1943. The inva­sion beaches, 5,000 yards in the back­ground, are being shelled by U.S. destoyers to little effect. In the far distance is one of two active island vol­canoes, Mount Bagana, rising 8,650 ft above sea level and belching smoke.

Right: Men from the 1st Battalion, 3rd Marine Division on Blue Beach 3 shortly after their landing. Marines mostly met limited resis­tance from the enemy, their landing on the island’s western coast having come as a surprise to the Japa­nese defenders. Enemy air­craft from Rabaul attempted to inter­dict the landing force, but their attacks proved ineffec­tive and they were largely fought off by U.S. and New Zea­land fighter air­craft for a loss of 26 Japa­nese planes. By the end of the first day, a small defen­sive peri­meter had been estab­lished and the majority of the first wave of trans­ports had unloaded their stores on the beach­head. A week later some Marine elements were able to take the offensive.

Bougainville Campaign: U.S. Marines at Japanese dugoutBougainville Campaign: U.S. Marines clear perimeter of infiltrators

Left: These Marines gathered for a group photo­graph in front of a Japa­nese dug­out at Cape Toro­kina, which they helped take. Within four to six weeks of their landing, the Marines and soldiers of the U.S. 37th Infan­try Divi­sion had expanded their peri­meter to a depth of 6 miles or so, estab­lished three air­strips (cour­tesy of Navy Sea­bees) from which to bomb Rabaul several hun­dred miles to the north­east, and essen­tially iso­lated the enemy defenders, though the Japa­nese still had a sub­stan­tial number of army (40,000) and naval (20,000) person­nel in the southern part of the island to harass the Americans.

Right: Japanese troops tried infil­trating Allied lines at night. At dawn U.S. soldiers would clear them out. In this photo, taken during the Battle of the Peri­meter (March 9–27, 1944), an M4 Sherman tank covers advancing infantry­men. Japa­nese casual­ties during the 2‑1/2-week battle were esti­mated to have been 5,400 killed and 7,100 wounded. In its after­math and cut off from out­side assis­tance, the enemy with­drew the majority of its forces into the jungle inte­rior and to the north and south ends of the island, where those not swept up by aggres­sive Austra­lian patrols (Phase 2) or swept off by mal­nourish­ment or tropi­cal diseases maintained a precarious existence until the end of the war.

U.S. Army Presentation: “Bougainville: A Step to Victory” (1943–1944)